US 12,228,951 B2
Vacuum exhaust system
Manabu Nonaka, Yachiyo (JP)
Assigned to Edwards Japan Limited, Yachiyo (JP)
Appl. No. 18/245,080
Filed by Edwards Japan Limited, Yachiyo (JP)
PCT Filed Oct. 1, 2021, PCT No. PCT/JP2021/036490
§ 371(c)(1), (2) Date Mar. 13, 2023,
PCT Pub. No. WO2022/075230, PCT Pub. Date Apr. 14, 2022.
Claims priority of application No. 2020-169296 (JP), filed on Oct. 6, 2020.
Prior Publication US 2023/0400868 A1, Dec. 14, 2023
Int. Cl. G05D 7/06 (2006.01); H01L 21/67 (2006.01)
CPC G05D 7/0688 (2013.01) [H01L 21/67017 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A vacuum exhaust system, comprising:
a first pump for performing vacuum exhaust from atmospheric pressure to a medium vacuum region;
a second pump connected in series with the first pump, and having a lower ultimate pressure than that of the first pump; and
a bypass valve provided in parallel with the second pump via a pipe communicating with an inlet port and an outlet port of the second pump,
wherein an exhaust gas from a vacuum chamber is exhausted via both of a passage of the second pump and a passage of the bypass valve,
wherein in low and medium vacuum regions, while the first pump and the second pump are being operated, the bypass valve is opened, and
wherein in medium and high vacuum regions, while the first pump and the second pump are being operated, the bypass valve is closed.